Weekend wearing on, a passing thunderstorm revealed the passenger-side windshield wiper was out of operation, likely the result of an electrical disturbance. When the sun was out in force, the bright chrome trim often proved blinding. Light rays bounced off the polished surfaces on the exterior body moldings, gauge cluster rings, and trim around the gear shifter gate, forcing us to avert our eyes at times. The chrome along the rear fascia around the tailgate edge also has the potential to sear retinas.

The biggest change to the diesel scene in recent years has been the increased use of selective catalytic reduction technology and urea-based diesel exhaust fluid, which the Touareg employs to achieve 50-state emissions compliancy. VW's fluid is branded AdBlue. Should the fluid in the tank run dry, the Touareg TDI will refuse to start. Around 5000 miles, a service interval reminder lit up in the cluster's multi-function display, indicating the fluid level was due for a top-off. According to Volkswagen, the 4.5-gallon AdBlue tank beneath the spare is capable of scrubbing 6000-10,000 miles worth of nitrous oxides under normal driving conditions. After the initial service reminder, a series of AdBlue-related countdowns will continue to urge the driver to refill, although we never made it past the first reminder even after cresting 7000 miles. Economical driving lends to economical AdBlue usage, but it can be unnerving to realize range is not only limited by the amount of diesel in the fuel tank, but by the amount of AdBlue as well -- which isn't exactly a widely consumed commodity available at every filling station.

The Touareg TDI once again proved its mettle during our roughly 2500-mile jaunt, delivering consistent performance while returning an impressive 24.3 combined mpg for the trip. We also went more than 500 miles on a single tank during one leg - take that, range anxiety. You'd be hard-pressed to achieve that sort of mileage and range from the majority of offerings in the mid- and full-size SUV segments, gas-powered or otherwise. While there's an uncertain road ahead in the U.S. market for larger SUVs like the Touareg (and diesel engines in general), our journey to the Rocky Mountains proved to us that the soon-to-arrive 2011 model at the very least has a strong base to build upon.

2010 Volkswagen Touareg TDI
Base price $44,350
Price as tested $59,850
Vehicle layout Front-engine, 4WD, 5-pass, 4-door SUV
Engine 3.0L/225-hp/406-lb-ft turbocharged diesel DOHC 24-valve V-6
Transmission 6-speed automatic
Curb weight (dist f/r) 5429 lb (53/47%)
Wheelbase 112.4 in
Length x width x height 187.2 x 75.9 x 68.0 in
0-60 mph 7.9 sec
Quarter mile 16.0 sec @ 83.5 mph
Braking, 60-0 mph 122 ft
Lateral acceleration 0.81 g (avg)
MT figure eight 27.6 sec @ 0.61 g (avg)
EPA city/hwy fuel econ 18/25 mpg
CO2 emissions 1.08 g/mile